Nakamura Sumiko, Satoh Ayaka, Aizawa Masaki, Ohtsubo Ken'ichi
Faculty of Applied Life Sciences, Niigata University of Pharmacy and Applied Life Sciences, 265-1 Higashijima, Akiha-ku, Niigata 956-8603, Japan.
Foods. 2021 Dec 30;11(1):97. doi: 10.3390/foods11010097.
Global warming has caused devastating damage to starch biosynthesis, which has led to the increase in chalky grains of rice. This study was conducted to characterize the qualities of chalky rice grains and to develop the estimation formulae for their quality damage degree. We evaluated the chalkiness of 40 rice samples harvested in 2019, in Japan. Seven samples with a high ratio of chalky rice grains were selected and divided into two groups (whole grain and chalky grain). As a results of the various physicochemical measurements, it was shown that the surface layer hardness (H1) of cooked rice grains from chalky grains was significantly lower, and their overall hardness was significantly lower than those from the whole grains. In addition, α- and β-amylase activities, and sugar contents of the chalky rice grains were significantly higher than those of the whole rice grains. The developed estimation formula for the degree of retrogradation of H1 based on the -amylase activities and pasting properties, showed correlation coefficients of 0.84 and 0.81 in the calibration and validation tests, respectively. This result presents the formula that could be used to estimate and to characterize the cooking properties of the rice samples ripened under high temperature.
全球变暖对淀粉生物合成造成了毁灭性破坏，这导致了水稻垩白粒的增加。本研究旨在表征垩白米粒的品质，并建立其品质损伤程度的估算公式。我们对2019年在日本收获的40个水稻样本的垩白度进行了评估。选择了7个垩白米粒比例高的样本，并分为两组（整粒和垩白粒）。各种理化测量结果表明，垩白粒煮后米粒的表层硬度（H1）显著较低，其整体硬度也显著低于整粒米粒。此外，垩白米粒的α-淀粉酶和β-淀粉酶活性以及糖分含量均显著高于整粒米粒。基于淀粉酶活性和糊化特性建立的H1回生程度估算公式，在校准试验和验证试验中的相关系数分别为0.84和0.81。该结果提出了可用于估算和表征在高温下成熟的水稻样本蒸煮特性的公式。
